Preliminary Analysis Of The Response To Temperature Stress In Capsicum Chinense And Capsicum Pubescens

Pepper(Capsicum L.)is an important vegetable crop.The growth and development of pepper are harmed by heat and cold etc.resulting in the decrease of yield and quality.Among the five cultivated species of Capsicum,the effect of temperature stress on annual Capsicum annuum L.was studied extensively,but that on Capsicum chinense Jacq.and Capsicum pubescens Ruiz.&Pav.was limited.In this study,through the analysis of physiological and biochemical,ultrastructural,transcriptome and metabonomic methods,the response of these two cultivated species to temperature stress was explored.The main results are as follows:I.The morphological,physiological and transmission electron microscopic observation of pepper leaves showed that:under temperature stress,the tolerance of C.chinense(HNUCC0001)was stronger;the plant morphological changes of C.pubescens(HNUCP0001)were more obvious,and the response of antioxidant system was stronger.2.Comparative transcriptome analysis showed that there was no significant relationship between the number of differentially expressed genes and the duration of high temperature stress in C.chinense(HNUCC0001),while longer time of high temperature stress in C.pubescens(HNUCP0001)was linked to more number of differentially expressed genes.Under low temperature stress,the number of differentially expressed genes in C.chinense(HNUCC0001)and C.pubescens(HNUCP0001)increased with the prolongation of stress duration,with more significantly differentially expressed genes in C.pubescens(HNUCP0001).3.The study of transcription factors showed that AP2,bZIP,MYB and WRKY all responded to high or low temperature stress,and the expression of related genes had no significant relationship with specific stress.HSF,transcription factor of heat stress,has different response to high temperature stress;CBF,transcription factor related to low temperature stress,has different expression.It is suggested that the different responses of C.chinense(HNUCC0001)and C.pubescens(HNUCP0001)to temperature stress are related to the different expression patterns of these stress-related transcription factors.4.KEGG enrichment analysis of differentially expressed genes showed that under high temperature stress,zeatin biosynthesis,phenylpropanoid biosynthesis,fatty acid prolongation and plant hormone signal transduction were significantly enriched;under low temperature stress,plant pathogen interaction,MAPK plant signal pathway,plant hormone signal transduction and diterpene biosynthesis were significantly enriched.5.Comparative metabonomics analysis showed that under high and low temperature stress,three metabolites of differential accumulation,auxin,abscisic acid and jasmonate,were identified in plant hormone signal transduction pathway.Under high temperature stress,jasmonic acid was up-regulated in C.pubescens(HNUCP0001);abscisic acid was down regulated in C.chinense(HNUCC0001),and j asmonic acid was up regulated in C.pubescens(HNUCP0001).6.The HSF family in C.chinense genome was analyzed,and 28 genes were identified.Comparative transcriptome analysis showed that 24 genes responded to high temperature stress(43 ?).